Zoology MCQs for NEET — Practice Questions with Answers

(a) The disruptive selection favours both the small and large sized (two different traits) individuals of a population. It eliminates the members with mean expression, thus producing two peaks in trait distribution. This may lead to development of two different populations.

(c) Natural selection is shown by the reproductive success of the members of a population best adapted to the environment. The organisms which adapt useful variations and successfully survive in changing environment and reproduce.

Sympatric speciation is the formation of species within a single population by reproductive isolation or without geographical isolation, eg., polyploids.

Richard Owen introduced the term homologous. The organs which have the same fundamental structure but are different in functions are called homologous organs like wings of mosquito and butterfly. But wings of butterfly is analogous to wings of a bird. Analogous organs are those which performing same function but having different basic structures.

Electron spin resonance method is the relatively most accuate method for dating fossils. Electron spin resonance dating is a relatively new, more precise and most accurate method of dating. 

In radioactive carbon method, C-14 is used. Its half life is 5730 years.

In Uranium-lead method, the uranium (${\mathrm{U}}^{238}$) is used. The half-life period of $\left(U^{238}\right)$ is $4.5\times {10}^{10}$ years. It means one-half of $U^{238}$ will convert to $L{d}^{206}$.

According to Hardy- Weinberg equation,

P² + 2PQ + Q² = 1

Where P = dominant allele frequency

          Q = Recessive allele frequency

          P² = Homozygous dominant genotype

          2PQ = Heterozygous genotype 

          Q² = Homozygous recessive genotype 

here p = 0.6 and Q= 0.4

therefore, 2PQ = 2 $\times$ 0.6 $\times$ 0.4 = 0.48

(b) Speciation of sympatric species is the formation of species within a single population without geographic isolation. Thus the subpopulation becomes reproductive isolated in the midst of its parent population.

Flame cells are the excretory organs in member of phylum-Platyhelminthes. Which are commonly called as helminths and Malpighian tubules are the excretory organs in member of phylum-Arthropda along with other insect.

Tendrils in plants are an example of divergent evolution because tendril is a modified axillary branch which modifies itself to support the plant. 

Nucleic acids (DNA and RNA) rich in carbon, hydrogen, oxygen, nitrogen and phosphorus are only capable of reproduction at their own, therefore considered as basic of life.